Hydration conditions as a critical factor in antibiotic-mediated bacterial competition outcomes

Abstract

AbstractAntibiotic secretion plays a pivotal role in bacterial interference competition, yet the impact of environmental hydration conditions on such competition is not well-understood. Here, we investigate how hydration conditions affect interference competition among bacteria, studying the interactions between the antibiotic-producingBacillus velezensisFZB42 and two bacterial strains susceptible to its antibiotics:Xanthomonas euvesicatoria85-10 andPseudomonas syringaeDC3000. Our results show that wet-dry cycles significantly modify the response of the susceptible bacteria to both the supernatant and cells of the antibiotic-producing bacteria, compared to constantly wet conditions. Notably,X. euvesicatoriashows increased protection against both the cells and supernatants ofB. velezensisunder wet-dry cycles, whileP. syringaecells become more susceptible under wet-dry cycles. In addition, we observed a reciprocal interaction betweenP. syringaeandB. velezensis, whereP. syringaeinhibitsB. velezensisunder wet conditions. Our findings highlight the important role of hydration conditions in shaping bacterial interference competition, providing valuable insights into microbial ecology of water-unsaturated surfaces, with implications for applications such as biological control of plant pathogens and mitigating antibiotic resistance.